Club fine Martin Scott over pre-season punch-up
Welsh has had two operations after initial surgery left him suffering from an infection which raised fears for his eyesight.
The 21-year-old is now on the mend but faces another four weeks out of action as a result of the bust-up at the club's training camp in Peebles last month.
It is understood Scott threw a punch after Welsh squared up to the former Ross County midfielder.
Calderwood has admitted there were concerns over Welsh's immediate future, but is hopeful the young midfielder will be back in action soon, while Scott continues to remain part of the Easter Road manager's plans and was on the bench for Sunday's 2-0 defeat to Celtic before starting in last night's friendly defeat at Blackpool.
Both players were the subject of an internal inquiry following the incident and Calderwood has confirmed that only Scott was hit financially as part of the disciplinary process.
He said: "Sean has had his operation.
"He's out (of hospital] now but it hasn't worked at all well for him.
"He had an infection and it's been very, very messy. I think he'll be another four to six weeks from now.
"They had to go in and do some work on the bone around the eye.
"But the surgeons were delighted with how he's come out of this last one and they don't envisage anything else going forward, and that everything will be okay.
"The disciplinary issue is done and dusted, the fine has been administered and Martin knows that. Only Martin was fined."